KUALA LUMPUR, Malaysia (AP) – Investigators are trying to restore files deleted last month from the home flight simulator of the pilot aboard the missing Malaysian plane to see if they shed any light on the disappearance, Malaysia's defense minister said Wednesday.

Hishammuddin Hussein told a news conference that the pilot, Capt. Zaharie Ahmad Shah, is considered innocent until proven guilty of any wrongdoing, and that members of his family are cooperating in the investigation. Files containing records of simulations carried out on the program were deleted Feb. 3, Malaysian police chief Khalid Abu said.

Deleting files would not necessarily represent anything unusual, especially if it were to free up memory space, but investigators would want to check the files for any signs of unusual flight paths that could help explain where the missing plane went.

Malaysia Airlines Flight 370 with 239 people aboard disappeared March 8 on a night flight from Kuala Lumpur to Beijing. Malaysian authorities have not ruled out any possible explanations, but have said the evidence so far suggests the flight was deliberately turned back across Malaysia to the Strait of Malacca, with its communications systems disabled. They are unsure what happened next.

Investigators have identified two giant arcs of territory spanning the possible positions of the plane about 7 hours after takeoff, based on its last faint signal to a satellite – an hourly “handshake” signal that continues even when communications are switched off. The arcs stretch up as far as Kazakhstan in central Asia and down deep into the southern Indian Ocean.

Police are considering the possibility of hijacking, sabotage, terrorism or issues related to the mental health of the pilots or anyone else on board, and have asked for background checks from abroad on all foreign passengers.

Hishammuddin said such checks have been received for all the foreigners except those from Ukraine and Russia – which account for three passengers – and that nothing suspicious has turned up.

“So far, no information of significance on any passengers has been found,” Hishammuddin said.

The crisis has exposed the lack of a failsafe way of tracking modern passenger planes on which data transmission systems and transponders – which make them visible to civilian radar – have been severed. At enormous cost, 26 countries are helping Malaysia look for the plane.

Relatives of passengers on the missing airliner – two thirds of them from China – have grown increasingly frustrated over the lack of progress in the search, in its 12th day on Wednesday. Planes sweeping across vast expanses of the Indian Ocean and satellites peering on Central Asia have turned up no new clues in the hunt.

``It's really too much. I don't know why it is taking so long for so many people to find the plane. It's 12 days,'' Subaramaniam Gurusamy, 60, said in an interview from his home on the outskirts of Kuala Lumpur. His 34-year-old son, Pushpanathan Subramaniam, was on the flight heading to Beijing for a work trip.

“He's the one son I have,” Subaramaniam said.

Before Wednesday's news briefing at a hotel near the Kuala Lumpur airport, two Chinese relatives of passengers held up a banner saying ``Truth'' in Chinese and started shouting before security personnel escorted them out.

``I want you to help me to find my son!'' one of the two women said.

Aircraft from Australia, the U.S. and New Zealand on Wednesday scoured a search area stretching across 305,000 square kilometers (117,000 square miles) of the Indian Ocean, about 2,600 kilometers (1,600 miles) southwest of Perth, on Australia's west coast. Merchant ships were also asked to look for any trace of the plane.

Nothing has been found, the Australian Maritime Safety Authority said.

China has said it was reviewing radar data and deployed 21 satellites to search the northern corridor of the search area stretching as far as Kazakhstan, although it is considered less likely that the plane could have taken that route without being detected by military radar systems of the countries in that region.

Those searches so far have turned up no trace of the plane, Chinese Foreign Ministry spokesman Hong Lei said Wednesday.

Indonesian Defense Minister Purnomo Yusgiantoro said Indonesia military radar didn't pick up any signs of Flight 370 on the day the plane went missing. He said Malaysia had asked Indonesia to intensify the search in its assigned zone in the Indian Ocean west of Sumatra, but said his air force was strained in the task.

``We will do our utmost. We will do our best. But you do have to understand our limitations,'' Purnomo said.

Hismammuddin said both the southern and the northern sections of the search area were important, but that ``some priority was being given to that (southern) area.'' He didn't elaborate.

Malaysian investigators say the plane departed 12:41 a.m. on March 8 and headed northeast toward Beijing over the Gulf of Thailand, but that it turned back after the final words were heard from the cockpit. Malaysian military radar data places the plane west of Malaysia in the Strait of Malacca at 2:14 a.m.

Thailand divulged new radar data Tuesday that appeared to corroborate Malaysian data showing the plane crossing back across Peninsular Malaysia.

The military in the Maldives, a remote Indian Ocean island nation, confirmed to Malaysia that reports of a sighting of the plane by villagers there were ``not true,'' the Malaysian defense minister said.

German insurance company Allianz said Wednesday that it has made initial payments in connection with the missing plane. Spokesman Hugo Kidston declined to say how much had been paid, but said it was in line with contractual obligations when an aircraft is reported as missing.